/Engine/Source/Runtime/GeometryCore/Public/Implicit/SDFCalculationUtils.h
Calculate twice signed area of triangle (0,0)-(X1,Y1)-(X2,Y2) return an SOS-determined sign (-1, +1, or 0 only if it's a truly degenerate triangle)
namespace UE { namespace Geometry { template<typename RealType> int UE::Geometry::Orientation ( RealType X1, RealType Y1, RealType X2, RealType Y2, RealType & TwiceSignedArea ) } }